1. Field of the Invention
The present invention relates generally to systems and methods for maneuvering satellites in orbit, and in particular, to a system and method for maneuvering a satellite to direct a one sensors at terrestrially based locations and for optimal collection of solar energy.
2. Description of the Related Art
Satellites typically comprise solar panels that are used to collect solar energy. The solar energy capabilities of such panes are maximized if the panes face directly into the Sun (that is, a vector normal to the plane of the solar panes is directed at the Sun). While solar panels are typically capable of rotating along one axis, the satellite itself usually also needs to be oriented to absorb maximum energy from the Sun.
In most circumstances, this poses no significant problems, as the moment of inertia of the satellite is small enough to permit such satellite orientations without undue requirements placed upon the satellite's attitude control subsystems. However, some satellite missions demand the use of sensor packages that substantially increase the satellite's moment of inertia about at least one of the satellite's axes. For example, sensor arrays used for space-based ground surveillance using radar can be quite large compared to other satellite structures, substantially increasing the satellite's moment of inertia. Such arrays may also be fixed to the satellite bus itself, thereby requiting the satellite bus to rotate to direct the arrays at the desired terrestrial location. As a result, such satellites can be asked to perform frequent and large rotations about axes with large moments of inertia. This places costly requirements on the satellite attitude control system, particularly the motive elements (e.g. thrusters, momentum wheels and the like) that are used to rotate the satellite.
What is needed is a system and method that permits satellites with large or extended payloads to achieve their mission while still permitting maximum solar energy absorption without the use of high capacity motive elements. The present invention satisfies this need.